Power driven wrench with reverse rotation limiting means



Aug. 25, 1959 D. E. MAIER 2,900,856

PowER DRIvEN WRENCH WITH REVERSE RoTATIoN LIMITING MEANS Filed May 7,1957 le E Maier* @UM J. m@

United States Patent Office 2,900,856 Patented Aug. 25, 1959 POWERDRIVEN WRENCH WITH REVERSE ROTATIN LIMITING MEANS Application May 7,1957, Serial No. 657,523 8 Claims. (Cl. 81-54) My invention relates towrenches and more particularly to power operated Wrenches.

It is an object of the invention to provide an improved wrench by meansof which a rotatable element, such as a nut or bolt, may be rotated anindefinite number of turns in one direction to tighten the element andwhich provides an unloosening rotation in the opposite direction to onlya limited extent.

It is another object of the invention to provide an improved Wrench ofthis type adapted particularly to be used with a reversible motor, themotor being driven in one direction for the purpose of rotating the nutin a tightening direction and being reversed for the purpose ofloosening the nut to the limited number of turns just mentioned. i

It is more specifically an object of the invention to provide a wrenchof this type which includes a one-way engaging device which disengagesfor the tightening direction of rotation but which `engages for the`loosening rotation and cooperates with motion limiting means to preventloosening beyond the limited number of turns mentioned.

It is a still more particular object of the invention to provide animproved wrench of this type having an input shaft driven by areversible motor and connected by gears to an output shaft, with aone-way clutch being disposed on the output shaft to allow itsunrestrained rotation in the tightening direction but engaging andcooperating with rotation limiting gearing to prevent more than thepredetermined number of turns of the output shaft in the looseningdirection.

The invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed, for carrying out theabove stated objects, and such other objects as will be apparent fromthefollowing description of a preferred form of the invention, illustratedwith reference to the accompanying drawings, whereinz` Fig. 1 is alongitudinal sectional view of a wrench embodying the principles of theinvention and shown connected with a conventional air motor;

Fig. 2 is a sectional View taken on line 2-2 of Fig. l; and

Fig. 3 is a sectional view on an enlarged scale taken on line 3-3 ofFig. 1. i

Like characters of reference `designate like parts in the several views.

Referring now to the drawings, the illustrated Wrench may be seen tocomprise an input shaft and an output shaft 11 at right angles to eachother, each rotatably mounted in a casing 12. The shaft 10 is rotatablydisposed in a hollow sleeve portion 13 of the casing 12 by means ofneedle bearings 14. The shaft 11 is rotatably disposed in the casing 12by means of a ball bearing unit 15 and a bearing sleeve 16.

j The input shaft 10 is formed on its end with a bevel pinion i gear 17which is in mesh with a bevel gear'` 18 disposed on the shaft 11. Thegear 18` is non-rotatably fixed with respect to the shaft 11 by means ofa hexagonal protrusion 19 formed on the shaft 11 and disposed in acorrespondingly shaped hexagonal recess 20 in the gear 18.

A one way clutch 21 is provided on the shaft 11. The one way clutch 21comprises an outer shell 22 provided with an inner cylindrical race 23and an inner hub 24 provided with an exterior cylindrical race 25. Thehub 24 is fixed on the shaft 11 by any suitable means, such as a setscrew 26. The outer shell 22 has a hub 27 formed integrally therewith,and the hub 27 is rotatably disposed on the shaft 11 by means of abearing sleeve 28.`

The clutch 21 includes a plurality of tiltable grippcrs 29 disposedbetween the races 23 and 25. The grippers 29 are provided with slots 30in their ends, and garter springs 31 are disposed in the slots 30.

A spur `gear 32 is fixed on the hub 27 and meshes with a gear 33 whichis rotatably disposed on a stud 34 threaded into the sleeve portion 13of the casing 12. A dowel pin 35 is fixed on the gear 33 and is adaptedto abut against a stop bar 36 positioned above the gear 33 in the casing12.

Any conventional reversible motor may be used for driving the wrench. Astandard air motor 37 is illustrated and has an output spindle 38. Thespindle 38 is provided with an axially extending tang 39 which fits intoa slot 40 provided in the end of the input shaft 10. The motor 37 isprovided with a control handle 41 which may be depressed for driving thespindle 38 in one direction and may be released for driving the spindle38 in the opposite direction.

The wrench is useful for tightening any suitable fastening Idevice suchas a nut 42 threadable on a bolt 43. An adapter socket 44 may be usedfor connecting the output shaft 11 of the wrench with the nut 42 and mayhave a quadrangular recess 45 for receiving a similarly shaped end 46 onthe shaft 11 and may have a hexagonal recess 47 to fit over the nut 42.p

The illustrated wrench may be used in operation for tightening the nut42 on the bolt 43 and then automatically releasing the nut 42 apredetermined number of turns. The socket 44 is positioned on the nut42, and the four sided shaft end 46 is disposed in the recess 45` so asto provide a connection between the output shaft 11 and the nut 42. Thelever 41 is then depressed so as to drive the output spindle 38 of themotor 37 and the shaft 10 connected therewith by means of the tang 39 inthe direction indicated by the arrow 48. The gears 17 and 18 drive theshaft 11 in the direction indicated by the arrow 49, and this rotationof the shafts 10 and 11 continues until the nut 42 is tightened on thebolt 43.

During this rotation of the shaft 11, the one-way clutch 21 may overrun,that is, the hub 24 and the race 25 formed thereon may rotate withoutany corresponding rotation of the outer shell 22 and the vouter race 23;and

under theseiconditions the grippers 29 are tilted against.

the action of the peripheral garter springs 31 so as to allow rotationof the inner race 25 with respect to the outer race 23.

During this rotation of the shaft 11, however, there is sufficient dragtransmitted from the inner race 25 to the outer race 23 through the-grippers 29 so that the outer shell 22 is rotated sufficiently as toturn the gear 33 and mo've the dowel pin 35 into its dotted lineposition in Fig. 2 in contact with the stop bar 36. The gear 32 isrotated under these conditions in the clockwise direction j as seen inFig. 2 by the shell 22, and the gear 33 is roclutch 2,1 completelyslipping, the outer race 23 being stationary and the inner race 25rotating, with the grippers 29 being tilted against the action of thegarter springs 31 into their disengaged positions.

nVllhen the lever 41 is released, the output spindle 38 of the motor 37is driven in the opposite direction, and the shaft 11 and the nut 42 arelikewise rotated in Yopposite directions through the gears 17 and 18.During this phase of the operation, the nut v42 is loosened. For thisreverse direction of rotation, the hub 24 fixed on the shaft 11 tiltsthe grippers 29 into their engaged positions, augmenting the action ofthe garter springs 31, so that the outer shell 22 is firmly fixed withrespect to the hub 24 and the shaftv11. The gears 32 and 33 then rotateinY the opposite directions, and the dowel 35 is moved into its fullline position as seen in Fig. 2 abutting the Stop bar 36 and preventingyfurther movement of the gears 3,3 and r32 andralso of the shaft 11through the one-way clutch 21 which is engaged at this time, Thus,although the motor 37 tends to rotate the shaft 11 to further loosen thenut 42, the stop dowel 35 and stop bar 36 prevent such furtherloosening, and the nut 42 has been loosened a predetermined numberofturns, such as, for example, one and one-half turns, by the rotationof the gear 33 in moving the dowel 35 from its dotted line position toits full line position as seen in Fig, 2.

My improved wrench advantageously tightens a rotatable locking member,such as for example, a nut, to a predetermined tightness depending onthe power and torque exerted bythe air motor 37. Then, upon reversal ofthe. air motor,v the wrench automatically loosens the nut a,predetermined number of turns depending on the dimensions of the s topbar 36 and the location of the` dowel 35 in the gear 33. This wrench isparticularly adapted for use in connection with the tightening of brakebands, for example, in a transmission which must be tightened so as tocompletely engage the associated brake drum and then must be loosened apredetermined amount so as to provide clearance between the drum andhand. In this case, the nut 42 is the tightening member for the band andis released a predetermined number of turns to provide the clearance.

Lwish it to be understood that my invention is not to be limited to thespecic constructions and arrangements Shown and described, except onlyin so far as the claims may be so limited, as it will be understood tothose skilled. in Vtheart that changes may be made without departingfrom the principles of the invention.

I claim:

l. In a wrench for use` on a tightening element lwhich is rotatable inone direction to tighten it and in the other direction to loosen it, thecombination of a rotatable shaft adapted to be connected in drivingrelation with the rotatable tightening element,` a one-way engagingdevice for limiting rotation of said shaft in a direction to unloosenthe tightening element, and lost motion mechanism connected with saidone-way device for allowing a predetermined rotation of said shaft inthe unloosening direction prior to 4said one`way device being effectivefor stopping further rotation.

2. In a Vwrench for use on a tightening element which is rotatable inone direction to tighten it and in the other direction to loosen it, thecombination of a wrench casing, a shaft rotatably disposed in saidcasing and adapted to be connected in driving relation with therotatable tightening element, a one-way engaging device on said shaftand engageable when said shaft is rotated in a direction to unloosen thetightening element, and a lost motion stop mechanism connected with saidone-way engaging device and with said casing for allowing apredetermined rotation of said shaft in the unloosening direction afterengagement of said one-way device and then being effective to stopfurther rotation in the unloosening direction.

3. In a wrench for use on a tightening element which is rotatable in onedirection to tighten it and in the other 4 directiri to lser it', thecombination of a rotatable out put shaft adapted to be connected indriving relation with the rotatable tightening element, a rotatableinput shaft, gearing connecting said shafts in driving relation, aoneway engaging device associated with one of said shafts and engageablewhen said one shaft is rotated in a direction to unloosen saidtightening element, and a lost motion stop mechanism connected with saidoneeway device for allowing predetermined rotation of said one shaft ina direction to unloosen said tightening element and then being effectiveto stop further rotation in the unloosening direction.

4. In a wrench, the combination of a rotatable member adapted to beconnected in driving relation with a rotatable tightening element, aone-way engaging device, and a lost motion mechanism, said one-wayengaging device and said lost motion mechanism being connected in seriesso that said one-way device engages and cooperates with said lost motionmechanism to limit the rotation of said member to a predeterminedrotation in one direction and said one-way device disengages to allowunlimited rotation of said rotatable member in the other direction.

5. In a Wrench, the combination of a wrench casing,` a shaft rotatablydisposed in said casing and adapted to be connected in driving relationwith a, rotatable tightening element, a one-way engaging device, and alost motion mechanism, said one-way device and said lost motionmechanism being connected in series between said shaft and said casingand said one-way engaging device engaging and cooperating with said lostmotion mechanism for limiting the rotation of said shaft to apredetermined rotation` in one direction and said one-way engaging de*vice releasing and allowing unlimited rotation of said shaft in theopposite direction. i

6. In a wrench, the combination of a rotatable shaft, a one-way clutchdisposed on said shaft, a rotatable gear, a stationary stop member, astop element carried by said gear and adapted to contact said stopmember to limit the. rotation of the gear to a predetermined part of arevolution, a second gear connected with said oneway clutch and driventhereby and in mesh with said rst named gear so as to limit the rotationof said shaft to a predetermined rotation in a direction to engage saidoneway clutch and said one-way clutch releasing for the oppositedirection of rotation of said shaft.

7. lIn a wrench, the combination of a rotatable output shaft adapted tobe connected in driving relation with a rotatable tightening element, arotatable input shaft extending at an angle to said output shaft, firstand second beveled gears providing a driving connection between -saidshafts, a one-way clutch on one of said shafts, a rotatable third gear,a stationary stop member, a stop element carried by said third gear andadapted to abut against said stop member to limit the rotation of saidthird gear, and a fourth gear connected with said one-way clutch to bedriven thereby and in mesh with said third gear Afor limiting therotation of said shafts in a direction to er1-V gage said one-way clutchreleasing for the opposite direction of rotation of said shafts.

8. In a wrench, the combination of a wrench casing, an output shaftrotatably disposed in said casing and adapted to be connected indrivingrelation with a rotatable tightening element, an input shaft rotatablydisposed in said casing at angles to said output shaft, rst and secondbeveled gears connecting said shafts for providing driving connectiontherebetween, a third gear rotatably mounted in said casing, a stop barcarried by said casing, a pin carried by said third gear and adapted toabut said stop bar to limit the rotation of said third gear to 'apredetermined part of a revolution, a one-way clutch disposed kon saidoutput shaft and comprising inner and outer races with a plurality oftiltable grippers disposed therebetween, said inner race being connectedwith said output shaft, and a fourth gear connected with said o'uterrace and in mesh with said third gear so as to limit 'rotation of saidoutput shaft 'to a predetermined rotation in the direction to engagesaid one-Way clutch and said one-Way clutch releasing for rotation ofsaid output shaft in the opposite direction.

References Cited in the file of this patent UNTTED STATES PATENTS 6Matchett .Tuly 8, 1952 Liefer Nov. 4, 1952 Taylor Sept. 8, 1953 OmerFeb. 14, 1956 May Feb. 28, 1956 Stough Aug. 28, 1956 Blacknton Mar. 26,1957

